NefMoto

Hi All,

I have a car with the twin charged TSI engine.

I originally had the car with stock parts and decided to go stage 1, all was running fine.

Then i decided to fit a full exhaust system and an uprated intercooler, for the first 100 or so miles after these hardware changes the car was driven spirited with most of the driving done above 4k rpm.
It was only at the point where i started to drive steady that i noticed that on over run below 3k RPM that intermittently the car will start bellowing what looks be to a charcoal colour smoke and some times under light throttle it will bellow out lots of smoke, some instances worse than others. It will also some times do this when pulling off slowly. The sometimes this issue does not occur at all.

To note, the car has not used any water or coolant since this issue has started.

What i will say is that under WOT i get no smoke at all and the smoke only seems to happen below 3K RPM, what i did notice on logging is that the car appears to go very rich when the smoke appears.
And i also got weird Lambda read outs when i did a 4th gear WOT Pull, the car actually requested Lambda 1 and then attempted to meet it right in the middle of a WOT at 6.2k RPM.

4th gear pull:
Actual Lambda:
3.4k = 0.932
3.9k = 0.967
4.4k = 0.948
4.8k = 0.878
5.3k = 0.844
5.7k = 0.824
6.1k = 0.972 <--- Just starts leaning out here Specified also shows specified as lambda 1 here on the logs..
6.4k = 0.891
6.7k = 0.821

I think i can hear a boost leak as I now get a screeching/high pitch whistle when coming onto boost.
I have placed the stock software on the car to see if that's the issue.
Although placing the stock software on the car has not cured the issue, there is certainly less smoke.

So my current thoughts:

- "I think the smoke is caused by" At low rpm/load i think the car is putting in loads of fuel for whatever reason and there's not enough air to burn the fuel properly hence all the smoke.
- Lambda sensor has been damaged when changing over to the new exhaust and is intermittently giving incorrect readings.
- Boost leak on either IC or IC pipework, so more air is getting into the intake after the MAF, then lambda is seeing lean and trying to rich out? (Just didn't think a boost leak could make so much smoke on a petrol)
- Something disrupted like gasket or something when needing to use some pressure to get the bracket to line up on the ill fitting "big brand name" exhaust.
- MAF gone faulty.

Tomorrow i will pull the bumper off an check for boost leaks and the ensure my lambda wiring is ok.

Apart from this, does anyone else have any other suggestions of what it could be on this twin charged engine?

Thanks

MAF?

I will check that, but wouldn't have MAF thrown a fault code on the engine module in VCDS?

Something like intermittent implausible signal or something?

Plus this only started to happen after IC and exhaust install, but it may just be a horrible coincidence.

Forgot to mention that the car is a 2012 with 20000 miles.

Also to note, there is no noticeable loss of power.

Whats the oil level looking like?

Oil level is just over half full and I have been closely monitoring the oil since this started happening and it's not dropped.  Nor has the coolant level.

Something else when cruising and then I use more throttle car initially goes leaner then richens out. I would not expect it to initially go leaner. I'm more inclined to think I have boost leak.

Half full? shouldn't it be full?

Well that depends as these engines are known to use oil. The 2.0tfsi also uses oil. But I think I know what the problem is.

I am able to replicate it, if I'm on vacuum for 20 seconds plus, like going down a hill the smoke starts and then when I accelerate it blows it all out.
As I get no smoke when on boost i'm inclined to think that it's valve stem oil seals.

or the compressor side oil seal..

you said the motor has like only 20,000ish miles right? valve stem seals should be fine but your spirited 4000+ rpm "on boost cruises" :P you described could very well have damaged the turbocharger. Also you explained you hear screaching noise coming on boost, that doesn't come from valve seals being bad that comes from a compressor/turbine wheel contacting its housing. If its really bad you can hear like a "tink tink...tatinktink" sound @ idle when you put your ear next to the TIP inlet.

I could be totally wrong here as I'm not familiar with the tfsi engines but I would bet on the turbo failing over the valve stem seals any day especially on a low mileage motor. Pull the intercooler piping just after the turbo and see if it's oily inside, if so, you know whats up..

A little update.  I pulled the plugs and found some oil on the plugs from cylinders 2 and 3. I think the boost leak type noise I can hear is due to a bad joint somewhere from when the new IC was fitted. It's almost like a secondary spool up/down noise.
Yup engine only has 20k on it. Investigations continue.

Oil?  Plugs should be shiny if oil.

If that, what is your charge pipes like?  Check your intercooler too for pools of oil.  If there's none there, it sounds like it's burning oil in the engine, in which case it'll be rings or stem seals.

A leak down test will confirm, but either way, it's not good..

Compression test is good. All cylinders showing good. No excess oil in charge pipes, ic, turbo or supercharger.
So I guess next thing to change is valve stem oil seals. Just seems odd that they would go so soon.

When you start it in the morn first thing do you get a puff of smoke out the exhaust?

Not every morning but if I'm quick and take a look around the back of the car there is a very slight puff of smoke on the odd occasion in the morning. I'm not having much luck with cars recently lol. I just managed to stuff up the immo on my gf's car so now that's a non starter too :-/

Good job on the immo! that sucks... you'll get it fixed... or you won't get laid ever again... lol

The smoke in the morn deal can be a sign of bad stem seals or worn stem guides.

Is it still under warranty? Put all the stock parts/software back on and send it to the dealer! With some luck they'll warranty out the repair costs.

Haha this is true hence my panic to fix it.

The difficulty is putting the stock parts back on, the inside bumper has to be cut to I stall larger IC so that is noticeable and the oem exhaust has to be cut off as it's a single unit from the centre back or the alternative was to take the whole axel off lol.
So that'll also be noticeable if it's got a joiner on.

I guess this is why you shouldn't modify a car too much when it's still under warranty,  it's got warranty until next year too... or did have....

I really hope it's not the guides as I think the guides are integral, I don't think they are an interchangeable part :-(

Oooooh fml.  Now my Stage 2 helix clutch is slipping on my Leon. It's only done 10k on that clutch and it was fairly heavy clutch toom

The dealer would most likely replace the head anyway. warranty or not

..really sucks if its the valve stem seals.

I wonder if they could have melted around the valve stem.  like the valves got too hot, most likely the exhaust valves. Whats the highest your EGTs have ever been?

From what I have read 1600F is scary hot. 12-1400F range is about max for safety.

From watching my EGT gauge: at idle 7-800F, a long idle drops it lower than 600F, at cruise about 1000F and if I get on it it climes quickly to around 1200F sometime higher but not much because of fuel enrichment.

sell the cars.. get a bicycle... damn dude!

The problem with these cars is no egt sensors and an egt model is used so depending on how the tuning has been calibrated or not in some cases and new diameter of exhaust and IC etc the figures are threw out a little. They are a lean burn engine too. But on this 1.4tsi i have seen calculated at 800c which is like 1500f. And tbh on my Leon tfsi i have seen as high as 900c under some really really heavy usage which is like 1650f. But again these are calculated temps. I guess it's possible they have melted around my valves.  Fortunately nothing has melted to date on the 2.0tfsi and that has been given some really heavy abuse and running 2 bar peak.

Lol its getting that way. If only I didn't live 60 miles from work :-(

I'm not too convinced man, blue smoke is usually indication that it's burning oil.

I did a little Googling and there is a PistonHeads thread talking about this - and one guy gets his engine replaced under warranty.

Some say it's a smokey engine but it's black smoke, which indicates over-fuelling.

If it's not loosing oil then I'd say there's nothing to worry about..  Can you post a picture of the plugs up?  If it's the stem seals, a long overrun at speed, in say second gear (for as long as you can), and then get on the throttle.  If you get blue smoke, then I'd be tempted to say stem seals.

But surely not at this age?  It's too young?

Well at the point it's happening there is no fuel as the car is on vacuum when on over run.

The symptoms you explain is exactly what I experience..... my logic...

Now i think this was caused by the fact that I didn't realise that the car had a litre of oil missing, so was only just touching the dipstick(i know schoolboy error)

This all happened after giving the car full throttle around a long swooping corner.

So when you consider that the car only takes 3.6 litre of oil and I had at least a litre missing (1 litre  between min and max on the dip stick) so I probably only had about 2.8 litre of oil left....
going round the long swooping corner at full throttle... i think part of the top end got a little oil starvation and the seals got HOT due to lack of oil and hardened onto the valves? Maybe?

I'm only getting oil on the plugs in cylinder 2 and 3, compression test is all fine too.

Next is to pull the cams and inspect the valve seals.

This car is breaking me down :-( valve stem oil seals replaced and still got exactly same problem. There is no piston wall damage so it can't be a ring.

Also the car only seems to smoke at lower RPM on overrun/engine brake,  if I drop the gear and keep the engine in higher rpm(3-4k) on overrun/engine brake it doesn't smoke. What on earth could it be? Could it be the turbo? But I don't see any oil in there?  Or maybe I don't see the oil as it's been blown into the engine once it's built up in the turbo?

Btw it is losing oil just very slowly.

any oil leaking through the compressor side oil seal would be blown from the turbo all through the charge air piping, even the throttle body would have a film of oil on it.

A leak on the exhaust side oil seal would cause instant smoke whenever oil pressure rises and might seem to dissipate at higher rpms because of the volume of exhaust moving through the pipes, also the pressure of the exhaust at the higher rpm on the seal would prevent oil coming through or much less oil coming though.

unless the supercharger runs oil through in a way that could leak into the intake tract, it's gotta be the turbo.

Well here's the thing? There is no excessive oil in the intake pipes or IC.  Inside SC was dry also and turbo also looked dry.  Whatever is happening it's certainly getting in cylinders. More cylinder 2 and 3. If I get the car to smoke near my house and use very little throttle plugs 2 and 3 are a little wet.

Valve stem seals have been changed and valve guides looked ok.

No scoring on the cylinder walls so surely can't be a piston or rings?

Can you show a pic of what you are calling "no excessive oil in intake pipes"? there really shouldn't be any oil. Sure, turbo motors generally consume oil but not anywhere close to the volume you are suggesting in an earlier post. 

The oil consumption is so small normally that you wouldn't notice a difference in the level on the dipstick or when you change the oil.

Assuming you pulled the head for the valve stem job, it can't be the head gasket as you installed a new one. ( I hope! lolol)

gotta be the turbo.

Hey,

I don't have a picture at the moment, but all the turbo cars i have had have had some level of oil within the charge pipes as the vent pipes are plumbed into the intake, therefore on boost you will get blowby.
There isnt a pool of oil, but if you rub your finger on the side of the pipe it is a tiny bit oily.

The head was not removed to do the stem seals, air can be pushed into the cylinder to bring the valve up and remove the spring, seal etc.

Whilst reading this, also consider that im only seeing oil in cylinders 2 and 3, if it was from the intake direction i would expect to see oil in all not just the middle 2 banks.

I have a theory, I believe that due to freeflow cat and larger IC that i have increased a pre existing issue as both of these things would increase vacuum. When fitting the stock exhaust and IC i do not see the smoke.

Completing some analysis on instances i have found on the internet of people complaining of high oil consumption, it seems that there is an extremely high percentage of 1.4tsi owners that have oil consumption issues.  I believe they are probably having the same issues as me but are not seeing the smoke as they have the stock exhaust installed and cat is cleaning/retaining a little until they go onto hard throttle.

When people have been experiencing high oil issues VAG have been replacing the engine, just before VAG decided to discontinue the engine they made a revised bottom end, block, pistons, PCV and vent hoses, the remained of the old parts are refitted to the new block. This whole revised crated engine comes in the form of the engine code "CTHE" i believe.

VAG have also been fitting the revised PCV and vent parts to the older engines to reduce vacuum and in turn the oil consumption a little, but i believe this is VAG's attempt to mask the real issue which i'm coming onto.
A couple other things which seem to reduce oil consumption is using 5/40 instead of 5/30 oil and people that make more use of manual mode on the DSG, which i have tested and yes if you keep the car in manual mode you are typically not using between 1-2k RPM much.... result no smoke. The fact i get no smoke is probably closely related to why people are using less oil with this method.

So it seems there is a mix up of things that are potentially causing oil to get past the pistons, there have been discoveries that the crank bearings cause a lot of vibration on the crank feeding through to rods and over time causing the rings to wear unevenly on the bore due to very slight movement. VAG have also created revised pistons and rings for the older engine too as the rings were wearing down very quickly, so i assume they have used a harder ring. There have also been suggestions that the older pistons are very slightly too small for the engine too, so with this combination of issues.......

I have found 2 instances of people in the same situation of me who managed to fix their engine from smoking.
The stock cylinders are 76.5mm so replacing them again with 76.5mm is probably not a good idea if we consider the above issues, as the bore may have slightly worn a little over time.
Both Wossner and CP manufacture slightly over size pistons to 77mm, so i'm going with the 77mm pistons and having the work done on my head to hone them in for a snug fit!

So this is the route i'm now taking and if this does not resolve the issue, then i will be issuing everyone an interesting bonfire invitation lol

So, i have not posted for a while....

But i am finally getting to the bottom of my issue, check out the below included pictures and look at the OE pistons... you can see evidence of gas blow by after the rings.... so i guess this is where my oil has been seeping through on vacuum.

(http://i.imgur.com/p3yCW1r.jpg?1) (http://imgur.com/p3yCW1r)

(http://i.imgur.com/TbzbZKn.jpg) (http://imgur.com/TbzbZKn)

(http://i.imgur.com/HUscwjU.jpg) (http://imgur.com/HUscwjU)

What is odd, is that a compression test showed all cylinders as good... maybe the issue starts once the engine has heated up..

Either way the following picture shows my new oversized pistons honed into the block for a nice snug fit, just waiting on getting my turbo back and the rebuild can begin! :-)

(http://i.imgur.com/WmTSOcO.jpg) (http://imgur.com/WmTSOcO)

I will provide a further update once it's up and running.

First of all 1.4 TSI is known to be failing really fast. It is a cost of downsizing IMHO.

For me it is quite normal compression test gave you normal reading as adding oil into cylinder will help to seal it during the test!

Very good point, now I am replacing the weak parts. Turbo and pistons... I'm hoping it'll be decent and work ok.

I know that the revised CTHE engine does not have these issues.

sorry to bring this back up, but I'm having a similar issue with my 2.0tfsi BPY, although not a bunch of smoke, but enough to look bad!
so did the new pistons do the trick??

Yes new pistons and refurbished turbo did the trick! Both were at fault.

Just to update this thread for anyone who landed here like me:

I am certain the issue this guy was having was down to his turbo oil seal. The blow by of his pistons was not really an issue and was not the cause of the smokey exhaust.

The turbo fitted on these engines internally run a high oil pressure - out of spec for the turbo manufacturer on a stock car, let alone a remapped one.
By doing a full turbo back exhaust, the oil seal pressures are no longer balanced and the net result is usually leaking oil straight into the hot exhaust - this is why you didn't see much oil in the intake tract / intercooler.

Its a thing to bear in mind with the 1.4 TSI engines/turbo - reducing exhaust back pressure will usually result in a smokey exhaust due to oil seepage past the turbos oil seal.
The solution is to change the oil restrictor bolt to the turbo, reducing internal oil pressure around the turbo seals.

Hi,
It later turned out to be multiple issues and yes the fact that the turbo does not have a stepped seal, not mounted level and the reduction in pressure does cause it to leak. But after closer inspection cylinder 3 had damaged piston ring, so this also did not help.

Fitting a stepped oil seal to the turbo does stop oil from leaking from the turbo. But you'll find this engine has multiple weak points for oil, NOT just the turbo.
Keep in mind that many of these engines have failed on stock hardware and setup, mostly with lost compression in cylinders and melted plugs. Which yes the later software can prevent the melted plugs, but does not prevent the fact that the rings /pistons can fail on stock setup.

Lots and lots of design flaws with this engine, hence why they do not produce it anymore. Very short lived setup for VAG.

Another update - car started bellowing blue smoke on vacuum again. Used a boroscope and found that the valve guide on cylinder 1 exhaust valve was leaking oil. So engine has been stripped,  new valve guides fitted on the exhaust side and all put back together again. No smoke so far.

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Damn that engine has given you some trouble!

Was it the valve guide or valve seals? - I only ask as i'm in the middle of rebuilding my engine, no problems prior other than a slightly rough idle on times but did find horrendously coked up intake and some minor/moderate pitting the valve seats which I lapped out.

I'm fitting forged pistons along with doing some other needed work - new camshaft adjuster that doesn't stick, new chain kit, new supercharger clutch etc.

I fitted all new valve seals whilst the head was off and I was lapping in valves. Didn't notice appreciable valve guide wear, and wouldn't know how to replace them without sending to a machine shop and then sourcing the guides for this engine would be interesting (VW don't sell them separately)

Hey, it was the valve guide, Yes I had to send the head off to have them machined. Replaced all exhaust valve guides, you may also want to consider fitting strong valve springs too as you get valve float at higher boosts and high RPM.

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I have the same problem in my CAVD. Misfire with 1.1bar after 6000rpm, but only cilinder 2

I changed plug, coil, and injector.. same problem

BTW, mine ended up being from oil in the intercooler. Installed a front mount and never had the issue again. I suspect from when my catch can line froze and crankcase pressures increased